Add legend to scatter

Hi.

I have coded the following for two scatters of measured values:

Plot2 = figure;
PV_TA2 = axes('Parent',Plot2);
hold(PV_TA2,'all');
scatter(T,I_K,'r', 'filled');
hold on
scatter(T,U_L,'g', 'filled');
xlabel('Temperatur in °C');
ylabel('Leerlaufspannung in mV | Kurzschlussstrom in mA');
title('Temperaturabhängigkeit','FontSize',14);
legend(Plot2,'I_K','U_L','Location','Best');
%Trend line
Poly2 = polyfit(T,U_L,1);
Poly3 = polyfit(T,I_K,1);
Trend2 = polyval(Poly2,T);
Trend3 = polyval(Poly3,T);
hold on
plot(T,Trend2, 'k', 'LineWidth', 1.5);
hold on
plot(T,Trend3, 'k', 'LineWidth', 1.5);

But the legend won't appear, so there must be something wrong.

How can I add a legend to my scatter. It should show a red dot or square depicting the short circuit current and a green one showing the open-circuit voltage.

Thanks for any hints!

Answer 1

[Azzi Abdelmalek]

legend('I_K','U_L','Location','Best');

[Marc Jakobi]

Thank you! How can I add text to each value?

[Azzi Abdelmalek]

What do you mean? and where to add text?

[Marc Jakobi]

Well the legend gives me a red dot with the string 'Ik' and a green one with the string 'Uk' behind it. I would like to change those strings to 'short circuit current' and 'open-circuit voltage'

[Azzi Abdelmalek]

This is not clear

[Marc Jakobi]

I am trying to do something like this:

legend('I_K', 'String', 'short-circuit current', 'U_L', 'String', ...
'open-circuit voltage','Location','Best');

I_K is a vector of measured short-circuit currents that change depending on the temperature and U_L are the open-circuit voltages that also change.

The legend I currently have on my scattter looks like this:

%red dot% 'Ik'

%green dot% 'UL'

I would like to change it to:

%red dot% 'short-circuit current'

%green dot% 'open-circuit voltage'

(with %dot% I mean a picture of a dot)

[Azzi Abdelmalek]

I'am not following you. If I've understood, you want just to replace the legend

legend('short-circuit current', 'open-circuit voltage','Location','Best');

[Azzi Abdelmalek]

Marc commented

Oh, now I understand it. I misunderstood the way the legend function works. I thought you had to use legend('I_K', 'U_L', 'Location', 'Best') with I_K and U_L referring to the vectors U_L and I_K that were scattered. I did not realize that the order of the strings determines which one refers to which variable.

Thanks for your help!

Answer 2

[Tony Castillo]

Dear all,

I am having issues meanwhile I attempt adding legend to my SCATTER figure, I use this line of code legend ({'k1_{Winter}', 'k2_{Fall}', 'k3_{Summer}', 'k4_{Spring}'},'Location','Best') but only print the first one, how to solve this?

Sincerely